Digital pictures or digital images, like other works of arts, provide copyrights to their owners. Digital images are easily accessed, transferred, downloaded, and manipulated by authorized and unauthorized parties. For example, by simply visiting a website, parties are able to copy digital images without authorization of the copyright owner. Furthermore, digital images may also be easily exchanged between parties, without the consent of the copyright owner. In many instances, unauthorized copied digital images may be considered pirated works or pirated images.
In certain instances, it is desirable to search for digital images that are copies of an original digital image. Such a search may, or may not, be to determine if the copied image(s) is/are pirated or not. Attempts may be made to search from thousands, if not millions of images, for copied images, which can amount to considerable effort or task.
Techniques to search for copied images, including detecting copied or pirated images, include watermark schemes; however watermark schemes and certain other searching schemes may be inefficient, when content of an original image (i.e., copyrighted image) is modified. To detect slightly modified images or near, different schemes or techniques are needed.